Christians in north-west Pakistan are demanding government protection following threats of bomb attacks if they do not become Muslims.

An unsigned letter received 10 days ago said they had to convert by Thursday.

Militants have been carrying out a sustained campaign to prevent "anti-Islamic" activities in North West Frontier Province (NWFP).

Last week they blew up a number of music and video shops in the towns of Charsadda and Tangi.

Living in fear

The Christian community, a tiny minority, received an anonymous letter demanding they convert or face the consequences.

The government says it is giving protection

The BBC's Barbara Plett in Islamabad says that while a few families have left, the rest live in fear.

Police say they have stepped up security at churches but Christians complain that not enough has been done to protect them.

"We are in great danger and need protection," said Michael John, the head of Pakistan's Catholic Church and a minority Christian parliamentarian.

The warning to Christians to leave Charsadda was delivered to his home.

'No response'

The town has recently been hit by violence - a suicide bomb attack in April killed at least 28 people at a rally in Charsadda. Interior Minister Aftab Ahmad Khan Sherpao, who was at the rally, escaped with minor injuries.

About 500 Christian families are living there - most migrated from India before the creation of Pakistan.

"Only the few policemen who patrol there on the motorbike are watching the Christians, but no significant security is provided," said religious minorities spokesman Shabaz Bhati.

"We are very much in fear that due to the lack of security these extremists will find a way to attack our people easily."

Mr Bhati also asked government officials to publicly condemn the threats but says he has got no response.